A printer apparatus (inkjet printer) has been conventionally known in which printing is performed on a printing medium formed in a sheet-like shape (hereinafter, referred to as a sheet-like medium) by executing control for feeding the printing medium in the front and rear direction with respect to a platen and control for ejecting ink while moving a printer head facing the platen in the right and left direction in a combined manner.
In recent years, it is required that printing is performed on a printing medium formed in a plate-like shape (hereinafter, referred to as a plate-like medium) in addition to a sheet-like medium by using the printer apparatus. In order to attain this requirement, a structure has been known in which, for example, support members for horizontally supporting a plate-like medium are provided on the front and rear sides of the platen. According to this structure, a plate-like medium is capable of being fed in the front and rear direction while being supported horizontally and printing is performed on the plate-like medium.
For example, in FIG. 3 in Patent Literature 1, a structure is disclosed in which a first support arm 101 and a second support arm 103 are provided on the front and rear sides of a platen 10 to horizontally support a plate-like medium 20 and the plate-like medium 20 is moved in the front and rear direction by rotating a feed roller 15. In the structure shown in FIG. 3 in Patent Literature 1, a plate-like medium 20 is moved in the front and rear direction while the under face of the plate-like medium 20 is slid on the upper face of the platen 10 by rotating the feed roller 15.
In the printer apparatus, it is important that a printing medium which is pinched between a feed roller and a pinch roller is fed with an accurate feeding amount which is proportional to a rotation angle of the feed roller for securing printing quality. Therefore, in order to prevent a printing medium from partially slipping on the feed roller, a number of roller assemblies respectively having a rotatable pinch roller is provided above the feed roller with a predetermined interval in the right and left direction.
Some of the roller assemblies are structured so that a clamp state for a printing medium can be changed. For example, a roller assembly has been known which includes a clamp pressure setting mechanism by which a pressing force (referred to as a clamp pressure) of a pinch roller that is pressed against the feed roller is capable of being changed and set depending on material, thickness and the like of a printing medium.